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Here’s Why a Bigger Engine Doesn’t Make a Car Faster

A few years ago, when there were very few choices in the car market with people only focused on fulfilling their basic A-to-B transportation needs. However, with a rise in competition, buyers have the luxury of choosing a car based on other factors as well.

Each vehicle segment (SUVs in particular) has multiple options, all of whom offer different performance characteristics that differentiate them from one another. One of the most important factors that determine driving pleasure, is the Power-to-Weight Ratio (PWR).

In this article, we will explain what it is, how to calculate it, and its effect on your car’s performance.

What is the Power-to-Weight Ratio?

In technical terms, a car’s PWR is the amount of power a vehicle has relative to its weight. Simply put, if there are two cars with the same engine power, say 100 HP, then the lighter car will be faster while the heavier car will be slower despite having the same amount of power.

Alfa Romeo Julia Quadrifoglio – PWR 0.29 HP/KG

How to Calculate Power-to-Weight Ratio

It is also quite easy to calculate PWR if you know the horsepower (hp) and the weight of a car. For example, if your car weighs 1000 kilograms (kg) and makes 100 hp, the PWR will be as follows:

100 / 1000 = 0.1 hp for every KG of car.

What Does it Mean?

There is a reason why sports car manufacturers such as Ferrari, Porsche, and Lamborghini focus on weight savings. They try to create an ideal PWR to make their cars go faster and feel more exciting.

Koenigsegg One:1 - PWR 1 HP/KG
Koenigsegg One:1 – PWR 1 HP/KG

For instance, Koenigsegg One 1 has a twin-turbocharged 5.0-liter V8 engine that produces 1,341 hp, while the whole car weighs only 1360 kg. This gives the vehicle an almost perfect PWR of 1 hp/kg (1:1) which is also the car’s name. The end result is a 0-100 kilometers per hour (km/h) time of around three seconds and a top speed of 280 mph (450 km/h).

In contrast, a Toyota Camry 2.4 Hybrid makes 176 hp and weighs 1,625 kg. It has a PWR of 0.1/kg. While that isn’t terrible, the Camry is not as fun to drive. This implies that having power that closely matches the weight allows for quicker acceleration and a better driving experience.

How Important Is It?

For the Pakistani market, PWR is quite important. Even though we don’t have race tracks to enjoy the performance of cars, that doesn’t mean that they have to be powerless.

Knowing that a car can deliver performance when needed is a huge benefit from an owner’s viewpoint. Furthermore, having more power and less weight also means that the engine wouldn’t be too stressed. This can also translate into a better fuel economy, as a heavier car with low engine power will run at a higher RPM more often, increasing fuel consumption. Though you should note that there are a number of other factors involved as well (road conditions, how a car is driven, etc.)

Underpowered engines have a tendency to overheat or fail in high-stress circumstances, while those with sufficient power can keep themselves and the owner relaxed in a challenging situation.

Typically, we observe cars with ideal PWR perform well at high altitudes and steep climbs. That is because ideal PWR allows for better road grip and power delivery (tires don’t skid easily), enabling the car to climb up a hill or pull out of a tough spot.

To sum it all up, a good PWR is not just important for racing, but for everyday driving as well.


  • Good article but incomplete… Was expecting a table of all Pakistani cars and their pwr…


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